1. Field of the Invention
The present invention relates to a sludge dewatering system that includes a concentration apparatus, which concentrates sludge while conveying the sludge on a top surface of a filter body, and a dewatering apparatus, which subjects the sludge concentrated by the concentration apparatus to pressure dewatering.
2. Description of the Related Art
A sludge dewatering system has been conventionally used, which includes: a concentration apparatus that subjects sludge in sewage, industrial wastewater, or the like to gravity filtration while conveying the sludge on a top surface of a circularly moving endless belt shaped filter body (filter cloth); and a dewatering apparatus that is arranged downstream from this concentration apparatus and subjects the sludge concentrated by the concentration apparatus to pressure dewatering, with a belt press type dehydrator or the like.
For example, in Japanese Utility Model Application Publication No. 62-25095 (hereinafter to be referred to as Patent Literature 1), a system is disclosed, in which, below a concentration apparatus that subjects sludge to gravity filtration with an endless belt shaped filter body, a belt press type dewatering apparatus that subjects the sludge concentrated by this concentration apparatus to pressure dewatering is arranged, and which is formed of a configuration in which one of belts forming the dewatering apparatus is used also as the filter body of the gravity apparatus. In this system, by addition of a first flocculant, such as a cationic polymer, to the sludge just before the gravity apparatus and addition of a second flocculant, such as an anionic polymer, to the sludge just before the dewatering apparatus, dewatering ratio of the sludge is increased.